How do I change to Left, Right, Front, Back Ortho Perspectives?
Lets try to clarify a few things:

Camera Settings vs. Viewport Settings



Camera and Viewport are two different things:


Viewport is mainly for temporary navigating and inspecting the 3d scene
Camera is mainly for defining final rendering perspective
You can switch Perspective/Orthographic for both Viewport and Camera separately &rarr; 1.
You can change focal length for both Viewport and Camera separately &rarr; 2.
You can set the Viewpoint of the Viewport, without changing the camera &rarr; 3.


And here the two of them get mixed up a bit:


If you set the Viewport to Viewpoint>Camera, it will adopt the Camera's parameters without changing them, but will switch back to its own viewport parameters on rotation/change of viewpoint. &rarr; 3.
If Lock Camera to View is activated while in Camera Viewpoint the viewport will be linked to the camera parameters any viewport change will directly be applied to the cameras position and parameters.


Viewport Background Images


Background Images assigned to front, top, back, etc Axis are only shown if the viewport is in the corresponding viewpoint (front, top, etc.) and set to orthographic mode.
(you seem to be in Camera Viewpoint with an orthographic Camera instead)